Sec Form 3 Filing - DBD Investors V, L.L.C. @ CoreSite Realty Corp - 2010-09-28

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person DBD Investors V, L.L.C. 2. Issuer Name and Ticker or Trading Symbol CoreSite Realty Corp [ COR] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 1001 PENNSYLVANIA AVE NW, SUITE 220 SOUTH 3. Date of Earliest Transaction (MM/DD/YY) 09/28/2010 (Street) WASHINGTON, DC20004 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares operating partnership units ( 1 ) ( 1 ) ( 1 ) Common Stock 25,275,390 I See footnotes ( 2 ) ( 3 ) ( 4 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other DBD Investors V, L.L.C. 1001 PENNSYLVANIA AVE NW SUITE 220 SOUTH WASHINGTON, DC20004 X Signatures /s/ R. Rainey Hoffman, attorney-in-fact 09/28/2010 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Beginning September 29, 2011, the OP Units will be redeemable for cash or, at the option of the Company, exchangeable into shares of Common Stock on a one-for-one basis. ( 2 )CoreSite CRP III Holdings, LLC, CoreSite CRP III Holdings (VCOC), LLC, CoreSite CRP IV Holdings, LLC, CoreSite CRP IV Holdings (VCOC I), LLC, CoreSite CRP IV Holdings (VCOC II), LLC and CoreSite CRP V Holdings, LLC (together, the "Limited Partners") are the record holders of 6,222,640, 1,260,550, 4,360,826, 742,637, 1,908,756 and 10,779,980 limited partnership units of CoreSite, L.P., respectively (collectively, the "OP Units"). DBD Investors V, L.L.C. exercises investment discretion and control over the OP Units through its indirect subsidiary, TC Group Investment Holdings, L.P., which is the managing member of each of Carlyle Realty III GP, L.L.C., CRP III AIV GP, L.L.C., Carlyle Realty IV GP, L.L.C., CRP IC AIV GP, L.L.C. and Carlyle Realty V GP, L.L.C. (Continued in footnote 3) ( 3 )Carlyle Realty III GP, L.L.C. is the general partner of Carlyle Realty III, L.P. which is the managing member of CoreSite CRP III Holdings, LLC. CRP III AIV GP, L.L.C. is the general partner of CRP III AIV GP, L.P., which is the general partner of CRQP III AIV, L.P., which is the managing member of CoreSite CRP III Holdings (VCOC), LLC. Carlyle Realty IV GP, L.L.C. is the general partner of Carlyle Realty IV, L.P., which is the managing member of CoreSite CRP IV Holdings, LLC. CRP IV AIV GP, L.P. is the general partner of CRP IV AIV GP, L.P., which is the general partner of each of CRP IV-A AIV, L.P. and CRQP IV AIV, L.P., which are the managing members of CoreSite CRP IV Holdings (VCOC I), LLC and CoreSite CRP IV Holdings (VCOC II), LLC, respectively. Carlyle Realty V GP, L.L.C. is the general partner of Carlyle Realty V, L.P., which is the managing member if CoreSite CRP V Holdings, LLC. ( 4 )DBD Investors V, L.L.C. is managed by a three person managing board, and all board action relating to the voting or disposition of the OP Units requires approval of a majority of the board. William E. Conway, Jr., Daniel A. D'Aniello and David M. Rubenstein, as the members of the DBD Investors V, L.L.C. managing board, may be deemed to share beneficial ownership of the OP Units beneficially owned by DBD Investors V, L.L.C. Such persons disclaim such beneficial ownership

Remarks: CRP IV-A AIV, L.P. and CRQP IV AIV, L.P. are parties to a Management Rights Agreement by and among CoreSite Realty Corporation (the"Company"), CoreSite, L.P. (the "Partnership"), certain of the limited partners of the Partnership (the "LimitedPartners") and certain other entities, pursuant to which the Limited Partners have assigned their rights under the Partnershipagreement to nominate two directors to serve on the board of the Company to CRP IV-A AIV, L.P. and CRQP IV AIV, L.P. DBD InvestorsV, L.L.C. exercises control over each of CRP IV-A AIV, L.P. and CRQP IV AIV, L.P. through its indirect subsidiary, CRP IV AIVGP, L.P., which is the general partner of each of CRP IV-A AIV, L.P. and CRQP IV AIV, L.P. DBD Investors V, L.L.C. is the general partnerof TCG Holdings II, L.P., which is the general partner of TC Group Investment Holdings, L.P., which is the managing member ofCRP IV AIV GP, L.L.C., which is the general partner of CRP IV AIV GP, L.P.Exhibit ListExhibit 24 - Confirming Statement

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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